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我终于能够在我的 java 应用程序中创建一个使用嵌入式数据库的服务器实例，如此处所述。当我从 Eclipse 运行它时，这可以正常工作，但这实际上不是我的目的（我的应用程序，在其他事物之间，为数据库提供新的节点和关系）。我有一个 Neo4j 盒子，它应该是我的服务器实例，我想将我的应用程序作为 JAR 文件部署在那里。这样，我想从那里访问网络界面。我已经对其进行了测试：在我的开发机器上运行 java 应用程序时，同一专用网络中的任何机器都可以毫无问题地访问该接口。当尝试将所有内容打包到 JAR 中以进行服务器分发时，就会出现问题。

具体的错误堆栈如下：

<!-- bean initialization stuff -->

Apr 11, 2013 1:14:30 PM org.neo4j.kernel.impl.transaction.xaframework.XaLogicalLog doInternalRecovery
INFO: Non clean shutdown detected on log [/data/production/graph.db/nioneo_logical.log.2]. Recovery started ...
Apr 11, 2013 1:14:32 PM org.neo4j.kernel.impl.transaction.xaframework.XaLogicalLog doInternalRecovery
INFO: Non clean shutdown detected on log [/data/production/graph.db/index/lucene.log.2]. Recovery started ...
2013-04-11 13:14:34,787 INFO [org.springframework.transaction.jta.JtaTransactionManager] - Using JTA UserTransaction: org.neo4j.kernel.impl.transaction.UserTransactionImpl@1b2fde11
2013-04-11 13:14:34,787 INFO [org.springframework.transaction.jta.JtaTransactionManager] - Using JTA TransactionManager: org.neo4j.kernel.impl.transaction.SpringTransactionManager@639c3c08
Apr 11, 2013 1:14:35 PM org.neo4j.server.logging.Logger log
INFO: Starting Neo Server on port [7474] with [40] threads available
Logger not configured, logging to std out instead: [FINE] Adding JAXRS packages [org.neo4j.server.rest.discovery] at [/]
Apr 11, 2013 1:14:35 PM org.neo4j.server.logging.Logger log
INFO: Mounted discovery module at [/]
Logger not configured, logging to std out instead: [FINE] Adding JAXRS packages [org.neo4j.server.rest.web] at [/db/data]
Apr 11, 2013 1:14:35 PM org.neo4j.server.logging.Logger log
INFO: Mounted REST API at [/db/data]
Logger not configured, logging to std out instead: [FINE] Adding JAXRS packages [org.neo4j.server.webadmin.rest] at [/db/manage]
Apr 11, 2013 1:14:35 PM org.neo4j.server.logging.Logger log
INFO: Mounted management API at [/db/manage]
Apr 11, 2013 1:14:35 PM org.neo4j.server.logging.Logger log
INFO: Mounted webadmin at [/webadmin]
2013-04-11 13:14:35,494 INFO [org.mortbay.log] - Logging to org.slf4j.impl.Log4jLoggerAdapter(org.mortbay.log) via org.mortbay.log.Slf4jLog
Apr 11, 2013 1:14:35 PM org.neo4j.server.logging.Logger log
INFO: Mounting static content at [/webadmin] from [webadmin-html]
Logger not configured, logging to std out instead: [FINE] Found [jar:file:/home/jaranda/cicerone/cicerone-crawlers/target/cicerone-crawlers-0.0.1-SNAPSHOT.jar!/webadmin-html]
Logger not configured, logging to std out instead: [FINE] Mounting static content from [jar:file:/home/jaranda/cicerone/cicerone-crawlers/target/cicerone-crawlers-0.0.1-SNAPSHOT.jar!/webadmin-html] at [/webadmin]
Logger not configured, logging to std out instead: [FINE] Mounting servlet at [/db/manage]
Logger not configured, logging to std out instead: [FINE] Mounting servlet at [/db/data]
Logger not configured, logging to std out instead: [FINE] Mounting servlet at [/]
2013-04-11 13:14:35,556 INFO [org.mortbay.log] - jetty-6.1.x
2013-04-11 13:14:35,915 INFO [org.mortbay.log] - NO JSP Support for /webadmin, did not find org.apache.jasper.servlet.JspServlet
Apr 11, 2013 1:14:36 PM com.sun.jersey.api.core.PackagesResourceConfig init
INFO: Scanning for root resource and provider classes in the packages:
  org.neo4j.server.webadmin.rest
Apr 11, 2013 1:14:39 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Root resource classes found:
  class org.neo4j.server.webadmin.rest.JmxService
  class org.neo4j.server.webadmin.rest.ConsoleService
  class org.neo4j.server.webadmin.rest.MonitorService
  class org.neo4j.server.webadmin.rest.RootService
Apr 11, 2013 1:14:39 PM com.sun.jersey.api.core.ScanningResourceConfig init
INFO: No provider classes found.
Apr 11, 2013 1:14:39 PM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate
INFO: Initiating Jersey application, version 'Jersey: 1.9 09/02/2011 11:17 AM'
Apr 11, 2013 1:14:40 PM com.sun.jersey.api.core.PackagesResourceConfig init
INFO: Scanning for root resource and provider classes in the packages:
  org.neo4j.server.rest.web
Apr 11, 2013 1:14:43 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Root resource classes found:
  class org.neo4j.server.rest.web.ResourcesService
  class org.neo4j.server.rest.web.RestfulGraphDatabase
  class org.neo4j.server.rest.web.DatabaseMetadataService
  class org.neo4j.server.rest.web.ExtensionService
  class org.neo4j.server.rest.web.CypherService
  class org.neo4j.server.rest.web.BatchOperationService
Apr 11, 2013 1:14:43 PM com.sun.jersey.api.core.ScanningResourceConfig init
INFO: No provider classes found.
Apr 11, 2013 1:14:43 PM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate
INFO: Initiating Jersey application, version 'Jersey: 1.9 09/02/2011 11:17 AM'
Apr 11, 2013 1:14:43 PM com.sun.jersey.api.core.PackagesResourceConfig init
INFO: Scanning for root resource and provider classes in the packages:
  org.neo4j.server.rest.discovery
Apr 11, 2013 1:14:46 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Root resource classes found:
  class org.neo4j.server.rest.discovery.DiscoveryService
Apr 11, 2013 1:14:46 PM com.sun.jersey.api.core.ScanningResourceConfig init
INFO: No provider classes found.
Apr 11, 2013 1:14:46 PM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate
INFO: Initiating Jersey application, version 'Jersey: 1.9 09/02/2011 11:17 AM'
2013-04-11 13:14:46,751 INFO [org.mortbay.log] - Started SelectChannelConnector@172.20.100.33:7474
Apr 11, 2013 1:14:46 PM org.neo4j.server.logging.Logger log
INFO: Server started on [http://172.20.100.33:7474/]
2013-04-11 13:14:47,616 INFO [org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler] - Initializing ExecutorService  'taskScheduler'
2013-04-11 13:14:47,714 INFO [com.twitter.hbc.httpclient.BasicClient] - New connection executed: Hosebird-Client-02, endpoint: /1.1/statuses/filter.json?delimited=length&stall_warnings=true
2013-04-11 13:14:48,346 INFO [com.twitter.hbc.httpclient.ClientBase] - Hosebird-Client-02 Establishing a connection
Apr 11, 2013 1:14:48 PM com.sun.jersey.spi.container.ContainerResponse write
SEVERE: A message body writer for Java class [B, and Java type class [B, and MIME media type application/json was not found
Apr 11, 2013 1:14:48 PM com.sun.jersey.spi.container.ContainerResponse write
SEVERE: The registered message body writers compatible with the MIME media type are:
*/* ->
  com.sun.jersey.server.impl.template.ViewableMessageBodyWriter

Apr 11, 2013 1:14:48 PM com.sun.jersey.spi.container.ContainerResponse logException
SEVERE: Mapped exception to response: 500 (Internal Server Error)
javax.ws.rs.WebApplicationException: com.sun.jersey.api.MessageException: A message body writer for Java class [B, and Java type class [B, and MIME media type application/json was not found
    at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:285)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1437)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
    at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:699)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:926)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: com.sun.jersey.api.MessageException: A message body writer for Java class [B, and Java type class [B, and MIME media type application/json was not found
    ... 22 more

我必须说我对 Spring、Maven 和 Neo4j 本身还是很陌生。我很迷茫如何摆脱这个问题。Web 界面实际加载但没有任何功能。见附图：

没有功能的 Neo4j Web 界面.

尽管存在此问题，但我的应用程序的后端工作正常，并且实际上创建了新的节点/关系。

我认为这里讨论了这个问题（或某种问题），但我并不清楚答案。

有什么建议么？先感谢您！

4

1 回答 1

4

我终于找到了一个解决方案，它成功了。我只是分享它，以防其他人遇到同样的问题。问题是在 jar 打包过程中 META-INF/services 下的某些文件被覆盖，因为默认情况下它们的内容不会合并。根据 maven-shade 插件参考：

提供某些接口实现的 JAR 文件通常附带一个META-INF/services/目录，该目录将接口映射到它们的实现类以供服务定位器查找。要将 同一接口的多个实现合并到一个服务条目中，可以使用ServicesResourceTransformer 。

所以在我的 pom 中添加这个变压器就可以了，例如：

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>2.0</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <transformers>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  ...
</project>

希望能帮助到你！

于 2013-04-11T15:48:47.370 回答